The present invention relates generally to work piece holders and, more particularly, to socket-wrench sockets.
Prior socket-wrenches have employed interchangeable sockets for use with various sizes of nut and bolt heads. For example, if the bolt has a ½ inch head, a ½ inch size socket is selected. However, in order to allow the nut or bolt head to be easily inserted within and removed from the socket, the socket opening is typically made slightly larger than the nut or bolt head for a given size. In this way, the socket can also accommodate slight variations in manufacturing tolerances for a variety of nuts and bolts heads all of a given nominal size.
This sizing creates an inherent gap between the nut or bolt head and the socket opening. Unfortunately, that gap means that when the socket is rotated by the socket-wrench, it actually engages the nut or bolt head at a corner of the nut or bolt head, rather than at the actual flat sides of the nut or bolt head. Thus, the rotational forces exerted on the nut or bolt head by the socket can create localized stresses at the corners of the nut or bolt head. Since the socket is typically formed from harder material than the nut or bolt head, these localized stresses, especially over time and/or where the bolt or nut has become somewhat rusted, can actually deform the corners of the nut or bolt head. This deformation is typically referred to as “rounding” or stripping of the nut or bolt head.
In addition, over time nut and bolt heads made from certain materials can corrode, oxidize or rust. When that happens, the material of the nut or bolt head, especially at its surface, can become softer or more brittle. This can result in the nut or bolt head being more likely to deform when rotation by the socket is attempted, especially where the corrosion of nut or bolt has also caused it to become more tightly lodged in place. In extreme cases, the corrosion can result in sufficient enlargement of the nut or bolt head that the socket size originally used to install it becomes too small to fit the nut or bolt head.
Further, nuts and bolts are sometimes installed or removed from locations that are remote and/or difficult to access either because of distance from the socket-wrench drive handle and/or interference with nearby objects or because of counterboring settings or the like. Previously, sockets have employed magnets therein or magnetized portions to retain the nut or bolt heads within the socket for such remote uses. However, corrosion of the nut or bolt head can interfere with the use of such magnets, and not all nuts and bolts are formed from magnetic materials.
Various prior devices have been suggested for use with rounded and/or corroded nuts and bolt heads, especially where the nut or bolt is in place and needs to be removed. Some, for example, have suggested that the nut or bolt be sawed, as with a hack saw. Some have suggested that pound in splitters be used to destroy the nut or bolt for removal. Some have suggested that a pound in socket be used to partially cut into the nut or bolt head to engage and grip it deeply enough to allow standard socket-wrench removal. Each of these methods will in many cases work to remove the nut or bolt. However, where the nut or bolt is installed at a remote or difficult to access location, these methods have been unavailable.
As an alternative, it has also been suggested that special sockets could be used to grip the nut or bolt head, having either a collect or chuck-like gripping surface or a plurality of longitudinally extending pins or poles that serve to grip the nut or bolt head. In each case, these arrangements tend to require relatively complex and/or expensive assemblies. Also, the mechanical efficiencies of these constructions often are not ideal, some, for example, requiring translation of axial force to radial force for the initial gripping and some not necessarily gripping the nut or bolt head on a significant flat portion of their sides, with the resultant risks of localized stresses. Also, certain of these constructions require radial dimensions so large that they cannot access counterbored nuts or bolt heads. Further, certain of these arrangements, such as the use of multiple pins over the entire socket opening, require additional insertion force to retract the non-gripping pin members.
Similar problems in work piece manipulation can occur in other applications besides socket-wrenches. In general, the solutions proposed have suffered from the same sort of inefficiencies, expenses and practical disadvantages.
Accordingly, it is an object of the present invention to provide an improved method and apparatus for workpiece manipulation. Specific objectives of this invention include providing an apparatus which:                a. does not round or strip the workpiece corners,        b. facilitates manipulation of workpieces with rounded corners,        c. facilitates retention and placement of workpieces to remote or limited access locations,        d. requires limited tool changes to handle multiple different workpiece sizes,        e. provides efficient use of application force,        f. is relatively simple to construct, use and maintain, and        g. is relatively inexpensive to manufacture.        
These and other objects of the present invention are attained by a socket-wrench socket having a plurality of longitudinally extending members therein mounted within wall circumferential slots of the workpiece-receiving opening of the socket and secured in place by a flexible web. These members have flat surfaces for engaging the workpiece and are biased into engagement with the workpiece by the web. These members and the slots are formed such that rotation of the socket causes the slots to exert radially inward camming force onto the members at the same time that rotational force is applied to the members. The members translate the camming force to flat surfaces of the workpiece for improved gripping, and translate rotational force to the workpiece for manipulation of the workpiece in the direction of that rotation.
Other objects, advantages and novel features of the present invention will be readily understood by those of ordinary skill in the art from the following detailed description and attached drawings.